1. Field of the Invention
The invention relates to cantilever storage racks for industrial use, and has particular application to cantilever racks used in conjunction with automatic stackers in which it is necessary to have accurate vertical arm location with respect to a base plane.
2. Description of the Prior Art
Baker et al U.S. Pat. No. 3,212,648 shows a cantilever storage rack having a pair of columns with vertically spaced apertures, arms with U-shaped brackets embracing the columns, and pins passing through apertures in the columns and brackets. Inclined edges on the bracket apertures create a wedging action of the brackets against the columns.
While the area contact of the pins and apertures, and the wedging action, of this cantilever rack have important advantages, it has been found that due to tolerance variations in the aperture locations, substantial variations in vertical height of the arms with respect to a horizontal base plane are not unusual. While this phenomenon is not worrisome if manually controlled loading and unloading of the cantilever storage racks takes place, the vertical distances of the arms from a base plane become quite important when loading and unloading is done with an automatic stacker. Conventionally, this type of stacker has a proximity indicator, for example on a mast, for each elevation. This means that for proper operation of the stacker, the cantilever arms at any level throughout the entire system must be substantially at the same vertical distance from a base plane.